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Signal Processing Apparatus, Droplet Ejection Apparatus And Signal Processing Method - Patent 8075076

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Signal Processing Apparatus, Droplet Ejection Apparatus And Signal Processing Method - Patent 8075076 Powered By Docstoc
					
				
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Description: This application claims priority under 35 USC 119 from Japanese Patent Application No. 2008-086939, filed Mar. 28, 2008, the disclosure of which is incorporated by reference herein.BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing apparatus, a droplet ejection apparatus, and a signal processing method. 2. Description of the Related Art There has been known a droplet ejection apparatus in which by applying a voltage to a piezoelectric element to deform the piezoelectric element, a droplet is ejected (e.g., see Japanese Patent Application Laid-Open (JP-A) No. 2000-94670). FIG. 12 is a circuit diagram showing a configuration example of a conventional drive circuit that applies a voltage to a piezoelectric element in a droplet ejection apparatus. As shown in FIG. 12, this drive circuit 300 includes a digital/analog converter 302, an operational amplifier 304, and a current amplifier circuit 306. The digital/analog converter 302, an operational amplifier 304 and the current amplifiercircuit 306 are connected in series. Moreover, piezoelectric elements 310 are each connected to the current amplifier circuit 306 via a switching element 308. When a digital signal indicating a voltage as a reference of a voltage to be applied to each of the piezoelectric elements 310 is input to the digital/analog converter 320, the digital signal is converted to an analog signal in thedigital/analog converter 302. The voltage of the analog signal is amplified by the operational amplifier 304 and the current thereof is current-amplified by the current amplifier circuit 306 to be output to each of the switching elements 308. Each of the switching elements 308 switches between two states of a conduction state and a disconnection state according to a control signal (not shown), and when the switching element 308 is in the conduction state, the voltage of the analogsignal output from the current amplifier circuit 306 is applied to t